Loop transfer means for circular knitting machines

ABSTRACT

Loop transfer jacks for circular knitting machines, especially single cylinder machines for closing tubular knitted goods, wherein the jacks are arranged in pairs, one jack of each pair for loop receiving, the other for loop delivering. The jacks are separately moveable back and forth in a pivotable half dial. The jacks of a pair have tips which provide cooperating hooks and tongues. These are constructed and arranged in such a manner that at least during the pivoting of the half dial the hooks and tongues have vertical surfaces contacting one another in a common plane, and have additional surfaces which provide a substantially continuous, smooth and unobstructed sliding path for the yarn loop to be transferred.

United States Patent [1 1 UNITED STATES PATENTS lngalls 66/95 X Miitze et al. Jan. 8, 1974 [54] LOOP TRANSFER MEANS FOR CIRCULAR 2,873,594 2/1959 15911611 66/95 KNITTING MACHINES FOREIGN PATENTS OR APPLICATIONS Inventors: Heinz Miitze, Karl-MarX'Stadt; 685,974 3/1965 Italy 66/95 Gerhard Barth, Dittersdorf; Klaus Kertzsche'" Zschopau, an of Primary Examiner- Wm. Carter Reynolds Germany AttorneyNolte and Nolte [73] Assignee: Veb Wirkmaschinenbau Karl-Marx-Stadt, Karl-Marx-Stadt, [5 7] ABSTRACT Germany 7 Loop transfer jacks for circular knitting machines, es- [22] Filed: Aug. 2, 1971 pecially single cylinder machines for closing tubular knitted goods, wherein the jacks are arranged in pairs, [211 App! 169573 one jack of each pair for loop receiving, the other for Related US. Application Data loop delivering. The jacks are separately moveable 3 continuatiomimpan of set 856,083 Sept 8 back and forth in a pivotable half dial. The jacks of a 1969, abandoned. pair have tips which provide cooperating hooks and tongues. These are constructed and arranged in such a 52 US. Cl. 66/95 manner that at least during the pivoting of the half dial 51 Int. Cl. D04b 15/02, D04b 9/56 the hooks and tongues have vertieal surfaces contact- [58] Field Of Search 66/95, 97, 19s g one another in a common plane, and have itional surfaces which provide a substantially continu- [56] Referen Cit d ous, smooth and unobstructed sliding path for the yarn loop to be transferred.

2 Claims, 18 Drawing Figures PAIENTEDJAN 8M4 3,783,644

sum 1 [IF 3 PRIOR ART INVENIQRS HEINZ MUTZE GERH D BARTH KLAU ERTZSCHER BY am/M ATTORNEYS INVENIQRS NZ MUTZE H BARTH- KLAUS TZSCHER BY 70%; 7M;

ATTORNEYS LOOP TRANSFER MEANS FOR CIRCULAR KNITTING MACHINES This is a continuation-in-part of US. Pat. application, Ser. No. 856,083, filed Sept. 8, 1969 now abandoned.

BACKGROUND AND NATURE OF THE INVENTION It has become usual to provide a circular knitting machine with a half dial wherein loop transfer jacks are moveable back and forth for receiving loops of one half cylinder and for transferring them to another half cylinder of knitting needles. The jacks are provided in pairs, the first jack of each pair having a hook, the tip of which points upwards in the loop receiving position of i the half dial, while the other jack has a tongue, the tip of which points downwards in said loop receiving position.

It has been a problem in such machines that yarn loops sometimes tended to hang up or slip through between the tips of hook and tongue. Visible faults then appeared in the knitted goods.

Faults were also encountered as transfer jacks could shift in relation to one another in vertical directions. Such shifting occurred since the vertical clearances between the jacks and their guides are critical and were not easy to control.

Therefore, it is an object of the invention to overcome the mentioned drawbacks of the prior art in order to assure functionally reliable loop transfer.

A further object is to construct and arrange the transfer jacks and guides in such a manner that reliable transfer of the sinker loops is assured.

Yet another object is to construct and arrange the transfer jacks and particularly their tips so that the loop will always reliably slide from the hook onto the tongue of a pair of cooperating jacks.

This has been achieved by providing a machine of the indicated kind with novel transfer jacks. They are constructed and arranged in such a manner that at least during the pivoting of the half dial the tips of the hooks and tonguesare in contact in a common vertical plane. Initially one tip slips onto the' other, and advantageously into a clearance thereof, so as to provide a substantially continuous, smooth and unobstructed sliding path for the yarn loop to be transferred.

DRAWINGS FIG. 1 is a sectional view of the new apparatus in loop receiving position;

FIG. 2 is a top view, taken generally along lines 2-2 in FIG. 1;

FIG. 3 is a bottom view, taken generally along lines 3-3, of an overlying conventional cam plate, which is designated as prior art;

FlG.-4 is an enlarged side view of a detail, according toa first embodiment of the invention;

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is an enlarged, perspective side view of a detail, according to a second embodiment of the invention, in a first position thereof;

FIG. 7 similarly shows the same detail in a second position thereof;

FIG. 8 similarly shows the same detail in a third position thereof;

FIG. 9 similarly shows the same detail in a fourth position thereof;

5 jacks, this FIG. accordingly being FIG. 10 similarly shows the same detail in an important, intermediate position thereof;

FIG. 11 shows, in a way similar to FIG. 10, the pivoting position of the tips in a conventional pair of transfer identified as prior art;

FIG. 12 is a fragmentary sectional view taken along lines l2l2 in FIG. 10;

FIG. 13 is a generally similar view taken along lines 13-l3 in FIG. 10;-

FIG. 14 is another generally similar view taken along lines l4-l4 in FIG. 10;

FIG. 15 is still another generally similar view, taken along lines l5-15 in prior art FIG. 11; this added FIG. therefore being identified as prior art;

FIG. 16 is a fragmentary plan view representing a portion of the structures more generally shown in FIG.

FIG. 17 is a fragmentary, sectional side view, taken along lines 17-17 in FIG. 2; and

FIG. 18 is a modification of FIG. 17.

the single cylinder circular knitting machine comprises a half dial 1, which is pivotable with its top downwards. The half dial is arranged within the needle cylinder and is mounted on an axle 3, journalled in a drive tube 2 which participates in the rotary motion of the needle cylinder. A rack 4a meshing with a pinion 4b in tube 2 causes the pivotal movement of the half dial. When the rack is raised, the half dial pivots counterclockwise as is indicated by the arrow in FIG. I. The top surface of the half dial has generally radially guide slots 5, wherein pairs of transfer jacks, 6 and 7, can slide. The sliding of the jacks is effected and controlled by projections or butts 8, 9 and 10, l 1 thereon, engaged by overlying cam plate 12, which has cam parts 13, 14 and 15 for either moving jacks in their guide slots or holding them against movement.

According to the invention and as shown in FIGS. 4 and 5, as a first embodiment, new and improved means are provided for assuring proper control of yarn loops. As already indicated, it has been found important to make sure that such loops will not hang up and remain suspended at the tip of a tongue, nor slip through between the tip of a hook and its tongue. To achieve this purpose, the invention aligns the tips of hook l6 and tongue 18 in a common vertical plane, designated in FIG. 5 as plane P. Both jacks, 6 and 7, are moveable in their respective guide slots along this plane, so that the tip of tongue 18 on jack 7 can slidingly enter a slot 21, parallel to this plane, which is formed in the tip of hook 16 on jack 6 and which upon such'entry is just filled by the tip of tongue 18. v

A second and preferred embodiment of the new and improved loop transfer means is illustrated in FIGS. 6 to 9. By additional FIGS. 10 and 11 it is compared with a relatively advanced loop transfer means according to the prior art, while FIGS. 12 to 15 show details of this comparison.

As shown in FIG. 6, this second embodiment uses a hook 16' comprising two substantially identical tip members, attached to jack members 6a, 6b,

respectively. The two tip members define, therebeoperation as the one shown in FIGS. 4 and 5. We prefer the embodiment of FIG. 6 since it is easier to manufacture and particularly easier to mass manufacture and to keep in serviceable condition than the embodiment with a slot, provided in a single tip member. In some cases, one of jack members 6a or 6b cna be made merely in form of a relatively short piece, secured to the other hook forming member. However, in many cases and particularly when the entire jack is only a minute piece of metal, it is simpler to make members 6a, 6b as separate coextensive metal parts and merely to move them and hold them identically by means of controlling cam structure.

As shown by FIGS. 7 to 10, the two portions of hook 16' always remain in the same position, relative to one another. They are only, as shown, in successive and different upward or downward orientations (FIGS. 6, 7 vs. 8, 9) or inclined orientations (FIG. 10). They, jointly, also are in successive and different positions, relative to the tongue (FIG. 6 vs. 7, 8; 10 vs. 9).

In FIG. 16, Roman numerals I to V indicate a set of different relative positions which (according to one loop-receiving program of the new apparatus) may prevail, simultaneously, as to five different pairs of jacks. It will be understood that each individual pair of jacks successively passes through substantially the same series of positions. Briefly, the five positions can be described as follows:

I. The complete pair of loop engaging jack structures 7 and 6a/6b, without a loop, is in inwardly retracted position.

II. Hook 16' has been moved outwards into loop receiving position. Needles N deposit a loop 17 in the hook (FIG. 6).

III. The tongue has been moved outwards to enclose the loop in an eye (FIG. 7).

IV. Both jacks (retaining their relative position as in FIG. 7) have been retracted, with the enclosed loop on the hook.

V. The dial then pivots (FIG. 10). A corresponding program is provided in the loop delivering position (FIGS. 8, 9), whereafter the dial pivots back.

During the pivoting movement of the half dial, when the two jacks assume positions such as the one shown in FIG. 10, yarn loop 17 slips or slides from hook 16' onto tongue 18. It is at this moment that the new construction of the jacks assures improved operation of the entire machine. This will become clear on comparison between FIGS. 10 and 11. As noted above, the novel transfer jacks have hooks (18) and tongues (16 or 16) the tips of which at least during pivoting, are in slidable contact in a common vertical plane (FIGS. 5,13), one of the tips sliding onto the other so as to provide an unobstructed sliding path (FIG. 10) for the yarn loop 17) to be transferred by the pivoting motion.

In the prior art construction, as shown in FIGS. 11 and 15, the hook H, contacting the tongue T, enclosed the yarn loop but did not guide the same, during the pivoting motion of the half dial, with sufficient safety. While the two jacks were being tilted downwards (see the downward arrows in FIG. 11) the yarn loop slid from hook H to tongue T, in relative upward motion (broken arrow in FIG. 10). In this latter motion, loop L encountered end surface S of tongue T (FIG. It tended to be stopped and suspended by the same, or to be wedged between the tongue and the hook, or in some cases to slip out between tongue and hook. This danger existed mainly when the yarn was fine-and thin, relative to the metal parts of the jacks, there being distinct limits of the dimensions to which these metal parts can be shaped, particularly in mass fabrication of transfer jacks.

These problems are overcome, at negligible expense, by the new construction. The operation thereof will be clear from FIGS. 10 and 12 to 13. Loop 17 first contacts hook 16, as shown in dotted lines in FIG. 10

and then moves relative to it, into the position shown in full lines. The corresponding conditions are also shown, in the same sequence, by FIGS. 12 to 14. Since the motion of the yarn loop always is relatively upward (dotted arrow in FIG. 10), while the metal structure pivots downwards, with a loop in it (full arrow), no condition of the type illustrated in FIG. 11 is encountered by the new structure. Initially, (FIG. 12) the yarn loop is held by the two elements of hook 16' and spread by the clearance 21 therebetween. As a result (FIG. 13) loop 17 slides from its lower to its upper position (FIG. 10) along the inner surfaces of hook and tongue, without encountering an end surface, such as surface S in FIG. 15, and without the corresponding obstruction encountered in the prior art (FIG. 15). The loop then simply slides on further onto the tongue of the new structure (FIG. yarn As a further advantageous feature, the new transfer jacks include a lug or loop spreader 19 on the receiving jack 6a, (FIGS. 8 and 9). This lug cooperates with tongue 18 to spread out yarn loop 17, in delivery position, so that needle N, operating in this position, can effectively engage the loop, by rising between the receiving and delivering jacks (FIG. 8) and by then intercepting the loop as the pair of jacks, reopened for delivery, are inwardly withdrawn (FIG. 9).

It will be clear from these explanations that the new system of transfer jacks operates more safely and more positively than the best prior art construction in transferring yarn loops from one to the other side of the needle cylinder. At the same time, the new jacks can be guided through their successive motions with adequate and in fact improved control.

In particular, for guiding these jacks in the vertical direction, there is disposed above the system of guide slots 5 (FIGS. 1 and 2), a cover 27, and new structure is provided for connecting this cover with half dial 1, outside the region of guide slots. Heretofore, the guiding of transfer jacks in such a system, has been unstable, particularly in the middle region of the half dial where the covers for the jacks-being necessarily thin--were not usually connected with the half dial in any direct way. According to the invention, means are provided which prevent any bending up of a thin wire which serves as cover 27. As shown in FIG. 17, such means comprise hook-shaped gripping members 28, soldered to half dial 1 to grip wire 27, in vertical positions radial of the half dial, and thus to secure it to the body of the half dial at any desired number of positions, between the path for individual jacks moving in and out of the half dial.

As further shown in FIG. 18, instead of a wire cover 27, there can also be provided a flat plate 27 in similar position as and serving in lieu of the wire with the aid of grippers 28'.

Referring finally to the required horizontal guiding of the transfer jacks, this can be done by guide slots 5 shown in FIG. 2, all of which are radial. These may be dimensioned to receive any suitable arrangement of transfer jacks, for example, as shown in FIG. 2, or alternatingly a pair of loop receiving jacks 6 and a pair of loop delivering jacks 7. A further variant is shown in FIG. 16, at 5' and 5"respectively, where a pair of delivery jacks 7 move in parallel direction (but usually in different cycles) in a single slot 5, whereas two pairs of receiving jacks 6a, 6b and 6'a, 6b, perform parallel motions in a slot 5'. Of course, further modifications are possible as to this horizontal guidance of the jacks.

What is claimed is:

l. A loop transfer half dial structure for a circular knitting machine, comprising a pair of loop transfer jacks jointly providing a loop-receiver hook and a loopdelivery tongue, the hook curvature being upward and the tongue curvature being downward when the half dial is in top-up position, the hook having a vertical slot; the hook and tongue having overlap, when the coincident positions, to provide an eye for loop transfer, to keep said hook contacting said tongue in a common vertical plane, and to present a continuously unobstructed edge to the loop to be transferred; and the structure including means to slide the tongue into and out of the slot to present in said coincident position, said continuously unobstructed edge.

2. A structure according to claim 1, wherein said hook comprises a pair of generally parallel hook portions to provide, therebetween, said slot. 

1. A loop transfer half dial structure for a circular knitting machine, comprising a pair of loop transfer jacks jointly providing a loop-receiver hook and a loop-delivery tongue, the hook curvature being upward and the tongue curvature being downward when the half dial is in top-up position, the hook having a vertical slot; the hook and tongue having overlap, when the coincident positions, to provide an eye for loop transfer, to keep said hook contacting said tongue in a common vertical plane, and to present a continuously unobstructed edge to the loop to be transferred; and the structure including means to slide the tongue into and out of the slot to present in said coincident position, said continuously unobstructed edge.
 2. A structure according to claim 1, wherein said hook comprises a pair of generally parallel hook portions to provide, therebetween, said slot. 